caa a22 4500 388022795 CHVBK 20180307124929.0 cr unu---uuuuu 161130e199805 xx s 000 0 eng 10.1557/JMR.1998.0194 doi S0884291400044307 pii (NATIONALLICENCE)cambridge-10.1557/JMR.1998.0194 Optical anisotropy of flexible polyimide thin films [Elektronische Daten] Optical anisotropy of thin films of an organo-soluble flexible polyimide based on 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride (HQDPA) and 2,2-dimethyl-4,4′-methylene dianiline (DMMDA) was detected by a prism-coupler technique. A mechanism is proposed, based on the model of gel film collapse. The degrees of optical anisotropy of the thin films were evaluated via the level of negative birefringence. The residual solvent in the films lessens the levels of negative birefringence so that the residual solvent must be evacuated. The levels of negative birefringence are independent on the solid content of the initial solution, but dependent on the thickness of the films. For a film of 16 μm thick, zero birefringence was achieved, postulated from the dependence of negative birefringence on the thickness of thin films. The relationship between the optical anisotropy and solution properties shows that the degrees of optical anisotropy of thin films on the same scale of thickness depend on macromolecular sizes in their dilute solutions. Copyright © Materials Research Society 1998 Li Baozhong Polymer Physics Laboratory, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China He Tianbai Polymer Physics Laboratory, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China Ding Mengxian Polymer Physics Laboratory, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China Zhang Ping Changchun Institute of Physics, Chinese Academy of Sciences, Changchun 130022, People's Republic of China Gao Fubin Changchun Institute of Physics, Chinese Academy of Sciences, Changchun 130022, People's Republic of China Jing Feng Changchun Institute of Physics, Chinese Academy of Sciences, Changchun 130022, People's Republic of China Journal of Materials Research Cambridge University Press 13/5(1998-05), 1368-1372 0884-2914 13:5<1368 1998 13 JMR https://doi.org/10.1557/JMR.1998.0194 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1557/JMR.1998.0194 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Li Baozhong Polymer Physics Laboratory, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China NATIONALLICENCE 700 1- He Tianbai Polymer Physics Laboratory, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China NATIONALLICENCE 700 1- Ding Mengxian Polymer Physics Laboratory, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China NATIONALLICENCE 700 1- Zhang Ping Changchun Institute of Physics, Chinese Academy of Sciences, Changchun 130022, People's Republic of China NATIONALLICENCE 700 1- Gao Fubin Changchun Institute of Physics, Chinese Academy of Sciences, Changchun 130022, People's Republic of China NATIONALLICENCE 700 1- Jing Feng Changchun Institute of Physics, Chinese Academy of Sciences, Changchun 130022, People's Republic of China NATIONALLICENCE 773 0- Journal of Materials Research Cambridge University Press 13/5(1998-05), 1368-1372 0884-2914 13:5<1368 1998 13 JMR CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge